Rib cage helps the Lungs to be protected from direct Injuries. Besides it has lot more functions.Have you ever analysed how you are Breathing while you Sitting, Walking and Running and all. We all don’t breathe optimally.As in we don’t expand our Lungs efficiently. The main reason for that is Our Rib cage doesn’t expand due to external stress applied to it. Not only that If your Rib cage doesn’t expand well it leads to many consequences like Muscular Imbalances that would actually cause Postural changes. Because when the Rib cage doesn’t move well it makes the Vertebrae stiff as well. Thus it makes the muscles around it get stiffer and leads to postural changes in the upper back.In terms of Breathing You need to practice how to Expand the chest during Breathing which should be followed during Walking and Running as well.